Numerous domino-type games have existed for centuries. The typical domino game consists of a set of flat rectangular blocks having faces divided into two equal parts which are blank or have one to six dots arranged as on a dice face.
Prior patented modifications to the domino game pieces have all retained the rigid structure of the domino piece while modifying only the manner in which symbols are displayed. For instance, U.S. Pat. No. 4,257,611 (Schmitz, Sr.) discloses a domino piece with concealable dots while British patent No. 8436 discloses domino pieces wherein the dot surfaces are recessed so to prevent wear. Further, U.S. Pat. No. 2,253,823 (Suteras) discloses a domino piece wherein the traditional dots are replaced with recessed and rotatable disks bearing numbers rather than dots. In each of these patents the domino pieces are rigid, and the symbols are displayed on only one side.
The traditional domino game is designed primarily for entertainment only and not for educational purposes. Modifications of the domino game to achieve such an educational purpose include those disclosed in French Patent No. 916,213 (Emanoylidis) wherein flags of different countries are used rather than dots, and U.S. Pat. No. 2,782,039 (Martin) wherein various combinations of numbers are used rather than dots to aid the players in learning mathematics.
Other patents of possible interest include U.S. Pat. No. 812,676 (Paul) and U.S. Pat. No. 927,183 (Staley) both of which disclose card games wherein the cards include U.S. currency denominations thereon.